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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #423539
Research Project: Innovative Manure Treatment Technologies and Enhanced Soil Health for Agricultural Systems of the Southeastern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: A biorefinery approach to recover nutrients, proteins, and methane from raw swine manure

Author
item CALVO-DE DIEGO, PAULA - University Of Valladolid
item GARCIA-GONZALEZ, MARÍA CRUZ - University Of Valladolid
item RIANO, BERTA - Instituto Tecnológico Agrario De Castilla Y León (ITACYL)
item Vanotti, Matias
item SANCHEZ-BASCONES, MERCEDES - University Of Valladolid
item MOLINUEVO-SALCES, BEATRIZ - University Of Valladolid

Submitted to: Journal of Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2025
Publication Date: 6/18/2025
Citation: Calvo-De Diego, P., Garcia-Gonzalez, M., Riano, B., Vanotti, M.B., Sanchez-Bascones, M., Molinuevo-Salces, B. 2025. A biorefinery approach to recover nutrients, proteins, and methane from raw swine manure. Journal of Environmental Management. 389. https://doi.org/10.1016/j.jenvman.2025.126254.
DOI: https://doi.org/10.1016/j.jenvman.2025.126254

Interpretive Summary: This study develops a biorefinery approach for pig manure valorization by combining different technologies for the recovery of nutrients, proteins, and methane. The technologies included gas-permeable membrane (GPM) to separate the ammonia, solid-liquid separation to separate organic particles, acid-base solubilization to separate phosphorus and proteins (SPP) from the particles, anaerobic digestion (AD) to produce biogas and combinations thereof. Using the GPM method, nitrogen concentrations were reduced by up to 90%. The SPP method provided a phosphorus extraction efficiency of 114% and a protein extraction efficiency of 86% from the solid fraction of pig manure. The methane yield was 1.9 times higher when nitrogen was recovered before AD, while phosphorus and protein removal resulted in methane yields comparable to swine manure (215 mL of methane per gram of volatile solids). A techno-economical study was carried out for the AD treatments, proposed in the biorefinery approach, high internal rates of return (IRR) were obtained, 21-37%, and a return of the investment in 3-5 years was obtained for all the treatments. In conclusion, this biorefinery concept is highlighted as a potential valorization approach for pig manure, resulting in the recovery of nutrients (ammonia and phosphorus), protein and energy in the form of methane.

Technical Abstract: The livestock industry is expanding rapidly, generating large amounts of manure rich in nutrients and energy. This study develops a biorefinery approach for pig manure valorization by combining different technologies for the recovery of nutrients, proteins, and methane. The technologies included gas-permeable membrane (GPM) to separate the ammonia, solid-liquid separation to separate organic particles, acid-base solubilization to separate phosphorus and proteins (SPP) from the particles, anaerobic digestion (AD) to produce biogas and combinations thereof. Using the GPM method, nitrogen concentrations were reduced by up to 90%, with total ammonia nitrogen (TAN) recovery rates ranging from 25 to 27 g N m-2 d-1. Solid-liquid separation did not significantly increase pH or N recovery increase. The SPP method provided a phosphorus extraction efficiency of 114% and a protein extraction efficiency of 86% from the solid fraction of pig manure. The methane yield was 1.9 times higher when nitrogen was recovered before AD, while phosphorus and protein removal resulted in methane yields comparable to swine manure (215.5 mL CH4 g-1 VS). A techno-economical study was carried out for the AD treatments, proposed in the biorefinery approach, high internal rates of return (IRR) were obtained, 21-37%, and a return of the investment in 3-5 years was obtained for all the treatments.